The Hidden Costs of Solar Delay

Massachusetts struggles with two climate strategies that increasingly collide in public debate: rapid decarbonization and forest protection. This presentation asks a simple question: What happens if Massachusetts succeeds in protecting more forest land but falls materially short of the solar deployment needed under its own climate plan? Using conservative assumptions and official planning data, we examine a scenario in which solar deployment achieves only 80% of planned targets between 2026 and 2050. The results suggest a hidden consequence: solar shortfalls do not merely delay clean electricity. They also create unbudgeted carbon emissions and enlarge the forest sequestration burden that future generations must somehow absorb.

This graph depicts the scale of the Massachusetts decarbonization challenge. Electric-sector emissions have already fallen sharply since about 2010. But the work ahead is still substantial. Under the Commonwealth’s climate plan, emissions from all sectors must continue declining rapidly through 2050, with remaining emissions offset through natural carbon sinks or, to-date unproven carbon capture and storage technologies. But, notice the electric sector. Electricity is expected to do double duty. It must continue reducing its own emissions while simultaneously helping transportation and building heating and cooling move away from fossil fuels. That makes the performance of the electric sector—and the growth of clean electricity supply—central to the entire decarbonization strategy.

Load Growth – Why Solar Matters

This figure highlights a central reality of decarbonization. Even while electric-sector emissions decline, total electricity demand is expected to more than double—from roughly 50 terawatt-hours today to 123 TWh by 2050. Why? Because transportation and building heating and cooling are expected to increasingly run on electricity rather than fossil fuels. So the challenge is not merely to clean up today’s electric grid. It is to build a much larger clean grid capable of powering electric vehicles, heat pumps and economic growth at the same time. By mid-century, solar alone may need to generate nearly as much electricity as the entire Massachusetts power system supplied in 2025. Without it, the entire decarbonization strategy becomes harder, more expensive, and less effective.

This slide illustrates the meaning of the Massachusetts carbon budget. Think of the carbon budget as a bathtub with a fixed capacity. Between 2026 and 2050, Massachusetts has a finite quantity of CO2 emissions it can release while still meeting its climate commitments—roughly 800 million metric tons. Today, we are pouring emissions into that tub at roughly 60 million tons per year. At that pace, the budget would be exhausted long before 2050. This is why timing matters. Every year of delay fills the tub further and leaves less room for the future. Emissions released in this decade cannot simply be undone later without much deeper reductions or decades of additional carbon sequestration. Forests and wetlands can help offset residual emissions, and carbon capture and storage may eventually contribute as well. But these sinks cannot expand quickly enough to rescue us from continued high emissions. The most reliable control we have is neither enlarging the bathtub, nor expanding our forests over 90% of the Massachusetts landmass. It is turning down the faucet—through efficiency and rapid deployment of clean electricity.

But Are We Building Fast Enough?

This chart depicts the actual solar deployment track record of Massachusetts in MW of installed dc capacity per year. Between 2020 and 2025, Massachusetts installed solar at an average rate of roughly 417 megawatts dc per year. Or only 312 MW per year in ac terms. That deployment rate was just sufficient to reach the state’s relatively modest 2025 benchmark goal of 4.5 GW. However, these weak deployment and adoption rates occurred during a period of generous federal home energy tax credits and – in 2020 and 2021 – one of much more favorable borrowing rates than seen today.

Planned Versus Actual Levels of Solar Deployment

This graph depicts the Massachusetts 2020-25 average actual solar deployment rate of 316 MWac/year projected over the next 25 years, to 2050. Next to this we see the expected rate of deployment under the 2050 Clean Energy and Climate Plan, the CECP. The CECP rate averages close to 1,000 megawatts (or 1 GW) per year over the entire planning period. But note the 1,200 megawatts per year pace through the next decade—nearly three times the recent pace. This discrepancy invites an important question. Can Massachusetts realistically move from recent installation rates to the much steeper deployment trajectory required for deep electric-sector decarbonization?

This question becomes more pressing when we compare CECP expectations with the forecast of regional grid operator ISO-New England. The CECP anticipates rapid growth in both wind and solar generation. Yet ISO-New England’s outlook suggests a slower trajectory especially for wind. And, its forecast for solar deployment has rates that remain well below the levels envisioned in the state plan. Whether these forecasts ultimately prove accurate is less important than what they imply. If Massachusetts does not substantially accelerate clean-energy deployment, the Commonwealth risks developing a widening gap between climate ambitions and clean-electricity supply. That possibility is what motivates the scenario explored in the remainder of this presentation. The exact numbers matter. But the broader message matters more. If current trends and infrastructure constraints persist, Massachusetts may not simply miss its solar targets by a small margin, it may miss them by a wide and climatically significant amount. That possibility frames the next question: What are the consequences if solar deployment falls significantly short of plans?

This slide outlines the central argument of the presentation. It tells a story of climate debt accumulating over time. When solar projects are delayed, downsized, or blocked, two climate costs emerge simultaneously. One cost is straightforward. When solar deployment falls short, Massachusetts produces less clean electricity and remains more dependent on fossil-fuel based generation. The result is additional CO2 emissions that exceed the Commonwealth’s planned carbon budget. The other cost is less obvious. Preserving forests at the expense of solar creates a false climate equilibrium for two reasons. First, the Massachusetts CECP already relies on existing forests to absorb 11% of our baseline emissions. Those same forests cannot also absorb the extra carbon emissions caused by continued solar deployment shortfalls. Second, there is a massive efficiency gap: it takes 5 to 10 acres of additional forest to match the carbon mitigation power of just one acre of solar. In other words, deployment delays may protect forest acreage in the short term while simultaneously increasing long-term sequestration demands.

That is the double-cost relationship shown here. Beginning in 2026 and moving towards 2050, each year of missed solar deployment creates a chain reaction. The first panel shows the Massachusetts annual solar deployment goals. The second shows a hypothetical 20-percent shortfall. That shortfall does not simply disappear. It produces a measurable loss of clean electricity, shown in the third panel. That lost generation then reappears as over-budget carbon emissions in the fourth panel. And finally, in the fifth panel, those emissions become a growing burden placed on forests—measured in the acres required to absorb carbon that clean electricity could have avoided in the first place. By 2030, the consequences have already multiplied through five years of accumulated shortfall. In 2050, the quantities have become substantial. But the 25 year totals are eye-popping: 116 terawatt-hours of lost clean electricity, nearly 40 million metric tons of unbudgeted CO2 emissions, and approximately 131,000 acres of forest which are now needed to offset that carbon debt. The message is straightforward: Opposition to solar deployment may preserve trees in one place—but unless emissions are reduced elsewhere, the climate system eventually requires forest carbon storage somewhere else.

To understand the true scale of our climate choices, we first have to establish the boundaries of the playing field. Look at the top bar. 147 million metric tons is the entire carbon budget for the Massachusetts electric sector through 2050. That is our absolute limit. Right below it, at 113 million metric tons, is the estimated maximum carbon sequestration we can expect from all three million acres of Massachusetts forests over that same time period. With those boundaries in mind, the physical reality of our tools becomes clear when we compare them side-by-side. If we preserve 100,000 acres of forest entirely untouched, it stores and sequesters about 30 million metric tons of carbon. However, utilizing that same 100,000-acre footprint for solar development avoids 136 million metric tons of emissions by actively displacing fossil fuels on the regional grid. Look at how those numbers interact with our baselines. The active prevention from just 100,000 acres of solar easily eclipses the passive sequestration of the entire state’s forest network, and it nearly matches the electric sector’s total carbon budget. Solar’s net carbon reduction power is 4 times more potent than forest sequestration on an acre-for-acre basis. When we prioritize passive sequestration over active clean energy, we are ignoring a tool with the sheer scale required to actually solve the math.

The map on the left illustrates what we will call the Prevention Path. Massachusetts contains roughly five million acres of land, of which about three million acres—60 percent—are forested. The inset circle represents approximately 30,000 acres, or only one percent of Massachusetts forests. That is roughly the amount of forest that would be required to accommodate the amount of additional solar deployment which could prevent Massachusetts falling 20% short of its full 2050 solar target. Now compare that with the map on the right. This is the Sequestration Path. If Massachusetts falls 20 percent short of its solar deployment goal, our analysis estimates that approximately 39 million metric tons of additional CO2e would accumulate in the atmosphere over the 25-year study period. A common response is, “Won’t our existing forests simply absorb that carbon?” Unfortunately, the answer is no. Those three million acres of forest are already performing an essential climate function, removing roughly six million metric tons of CO2e every year. Their sequestration capacity has already been committed. Offsetting an additional 39 million metric tons of CO2 would require the equivalent of about 131,000 more acres of forest, more than three times the acreage represented by the Prevention Path. Could we simply claim carbon removals from forests somewhere else? On paper, perhaps. But if every jurisdiction relies on someone else’s forests to offset its own emissions, the accounting no longer represents additional climate benefit. It simply reallocates the same finite carbon sink. That is the central message of this presentation. Forest conservation and clean-energy deployment are not objectives that are mutually exclusive. They are complementary climate strategies. But if solar deployment falls short, the carbon debt does not disappear, it accumulates, increasing the demand for more dramatic CO2 emissions reductions or for forest sequestration somewhere else.

Forests as Climate Infrastructure

Forests are among our most important forms of natural climate infrastructure. But climate infrastructure, like any infrastructure, has physical limits and scale requirements. Massachusetts currently emits approximately 60 million metric tons of CO2-equivalent annually. At a sequestration rate of 1.5 metric tons per acre per year, offsetting those emissions would require roughly 40 million acres of forest. This map shows the geographic magnitude of that requirement. It represents a forest acreage comparable to the combined forests of all 6 New England states, New York and beyond. This comparison highlights an important reality: Forest preservation and forest sequestration are valuable climate tools—but the land requirements become enormous when sequestration is asked to compensate for large continuing emissions streams. Seen through this lens, forests are not a substitute for emissions reductions. They are a partner to it.

Massachusetts forests have historically contracted and expanded with changes in technology, as well as human land-use priorities. The bygone phases in the development of the Massachusetts economy relied on lands and waters within our own boundaries to provide food, heat and building materials for the population. Today, we are proud of and protect our forests, almost 60% of our landmass. Yet this luxury is enjoyed only at a cost to other lands, other people, other wildlife habitats. Based on published in-state wood harvesting rates per harvested acre, Massachusetts presently satisfies our consumption requirements for wood-related products only through the harvesting of 573,000 acres of non-Massachusetts forest. On top of this, 6.4 million acres of out-of-state crop and grazing lands are dedicated to the provision of about 90% of our food requirements. It should be apparent that our rich forested landscape comes at a price that other states and countries must pay. Is the protection of our Massachusetts forests somehow more important than the protection of the forest and grassland of other US and global communities? The same question can be posed relative to the exploitation of land, resources and human health that accompanies the importation of nearly 50% of Massachusetts electrical energy requirements from beyond our borders. The modern challenge is to manage both forest conservation and clean-energy deployment together. Delayed clean-energy deployment may preserve some Massachusetts forests today but only by buttressing the demand for the forest and energy resources of others beyond our borders.

Conclusion

The lesson from this analysis is straightforward. Massachusetts cannot preserve and sequester its way to net zero. Forests are indispensable climate allies. They store carbon, protect biodiversity, and help offset emissions we cannot fully eliminate. But forests are not substitutes for clean energy deployment. If Massachusetts falls short of solar deployment targets by only twenty percent, the result is not simply slower progress. It is a double climate cost: less clean electricity today and a larger carbon sequestration burden tomorrow. The emissions released through missed solar deployment are not theoretical. They are real and they accumulate. And once released, they cannot be pulled back. They must be offset either with more drastic emission cuts down the road or by expanding forest sequestration far beyond lands under the state government’s control. Under the scenario explored here, preserving forest from solar development today would still leave Massachusetts needing roughly 131,000 additional forest acres simply to absorb the resulting carbon debt. So, the real question is not whether forests matter. They do. The question is whether we will use a modest share of forest land strategically to avoid far larger carbon obligations later. Over 25 years, Massachusetts could dedicate roughly 3 percent of its forest land to achieving the clean electricity system envisioned in the CECP—while generating power for EVs and heat pumps and avoiding tens of millions of tons of CO2 emissions. Or we can delay, constrain deployment, and discover too late that the forests we sought to save must now shoulder much of the climate burden we chose not to prevent. That is the choice before us.