Solar Farms: Are They Good for Maine?

On October 25, Cathance River Education Alliance and Brunswick-Topsham Land Trust hosted a panel of experts to help us understand solar farms, their benefits, and their impacts. You can watch the recording here or at the end of the highlights/summary below.

Overview and reflection

Implicit in the discussion was the pressing need for renewable energy to achieve climate goals. We need clean energy and we need it quickly. It was noted during discussion that the amount of solar energy called for in Maine’s climate plan would occupy around 22,000 acres, or 0.1% of Maine’s land surface. (For context, Maine’s public roads cover over 127,000 acres and golf courses occupy an estimated 15,000 acres.)

We should be careful to site solar in appropriate locations, staying away from sensitive areas. But solar has several big advantages: 1) it treads relatively lightly on the landscape compared to residential, commercial, and industrial uses; 2) land can be returned to its prior use relatively easily when its use as a solar farm is discontinued; 3) the amount of time it takes to permit and build solar farms is relatively quick, compared to other energy sources.

Two questions not directly addressed in this discussion, but worthy of consideration: Are there other alternative forms of renewable energy that are ready to go and can produce energy in the amounts and time frame needed? What are we doing, individually and collectively, to reduce our demand for energy?

Program Highlights

Our moderator and panelists:

  • Moderator: Fred Horch, Co-Founder of Spark Applied Efficiency, a company that helps businesses transition to clean energy, moderated the discussion.
  • Fortunat Mueller, Co-Founder and President of ReVision Energy, which has installed everything from rooftop solar on residences to large commercial solar farms;
  • Adam Desrosiers, Vice-President of Electric Operations at CMP overseeing delivery of electricity to CMP customers; and
  • Brooke Barnes, Principal in Environmental Services at Stantec, with extensive experience including evaluating and permitting wind and solar projects.

First, a few definitions:

  • Solar farm – generally, a solar installation that is NOT located where the power it generates is being consumed.
  • Distribution lines – the grid on which electricity is delivered consists of ‘distribution’ lines and ‘transmission lines. Distribution lines carry electricity shorter distances and are generally lower voltage than transmission lines. They are similar to local streets, delivering electricity to customers, although there are different types of distribution lines that carry different amounts of voltage. Higher voltage distribution lines are more like arterial roads.
  • Transmission lines – ‘transmission’ lines are higher voltage lines moving large amounts of electricity longer distances, more equivalent to highways.
  • Utility-scale solar – very large installations of solar panels, typically involving thousands of panels and hundreds of acres. Because of the large amount of power they generate (e.g. 100 MW range), these projects can only connect to transmission lines and typically must build transmission lines to connect to the grid and build or upgrade substations.
  • Load – consumption of electricity.
  • Dispatchable energy – an energy source that can be easily turned on and off to meet demand. Fossil fuel plants are often used for this purpose currently.

A little background on the grid

The electric grid does not have uniform capacity to receive power from new solar farms (or other energy sources. Some geographic locations require upgrades (to substations or distribution lines) to accept new sources of power. This is an important factor in where solar farms are located.

In general, solar farms generating 5 MW or less of power are easier to fit into the existing grid without upgrades that add to the cost of the project. So, many solar developers look for land in places where the grid has capacity to receive additional power. CMP makes ‘capacity maps’ available for this purpose.

Maine is part of ISO-NE, a regional entity serving New England that coordinates the flow of electricity on inter-state high voltage transmission lines, oversees wholesale energy markets, and plans to ensure future power needs will be met. ISO-NE guides the movement of power from Canada and Maine to points south and has a role in approving utility-scale energy sources.

How does solar differ from other energy sources?

  • Wind, solar, and hydro power sources have different energy production profiles. The amount of energy they produce depends on weather, time of day, and other factors. None produce energy as consistently as nuclear or fossil fuel burning plants.
  • Once the grid has more than 25-30% energy sources that produce intermittently, grid operators have to plan for more ‘dispatchable’ energy sources or energy storage (e.g. batteries). As we remove fossil fuel dispatchable resources from the grid, we have to find others to replace them.

What are some of the economic forces influencing solar farm siting?

  • Smaller-scale solar farms (<5 MW) can plug directly into Maine’s distribution system. In most cases, the cost of upgrades to the distribution system is limited. However, solar developers must find locations on the grid that can handle the additional power, where available land is close to utility lines.
  • Large projects (utility-scale) usually have to build transmission lines to connect to the grid and often have to upgrade or build multi-million-dollar substations. These projects require a very large footprint to generate enough power and associated income to offset those high costs. Because of the scale, capital costs are lower, but transaction costs are the same as smaller projects.
  • Policies play a role in solar farm siting.
    • Net metering allows solar energy generators of up to 5 MW to receive full credit for solar energy sent to the grid. Under this system, solar energy users can use credits earned when they generate solar energy in excess of their needs (sent to the grid), to cover their needs when they aren’t producing enough solar.
    • Projects occupying 20 or more acres receive a higher level of review by Maine DEP, which costs more and adds to the permitting time. So, there are many projects of 19.9 acres.
    • Maine requires projects over 5 MW to connect to the transmission system (which generally increases costs), so many projects stay below 5 MW.
  • The technology is advancing. Panel size is increasing, and panel efficiency increases by several percent annually. Over time, this reduces the amount of land needed to produce a given amount of solar power.
  • As more solar farms are added to the distribution system, more upgrades become necessary.

How much solar is there in Maine? How much more do we need, according to Maine’s climate plan, Maine Won’t Wait (MWW)?

  • MWW set a goal of electrifying everything (i.e. converting everything that requires fossil and other nonrenewable fuels to electric power) and reaching 100% clean energy by 2050.
  • The plan calls for 7,500 MW of solar energy (1/3 of total energy supply needed), with wind and hydro supplying the other two-thirds.
  • Maine currently has 500 MW of solar. We need to add ~500 MW/yr to reach MWW’s goal.
    • This seems like a lot, but half the 500 MW has been added in the past two years.
    • There’s a lot in the queue. 2,000 MW of solar is in construction or in the queue to be studied.
    • Solar farms are relatively quick to build compared to other energy sources. Small projects: 9 months to permit, 4-5 months to build, assuming no upgrades required by CMP.
    • Larger projects requiring upgrades, ISO-NE review, and other permits take much longer.
    • Barriers to more solar – there is a policy backlash to the recent increase in solar farms in the form of legislation, moratoria, and restrictive ordinances on solar farms. This will likely slow solar construction.
    • Note: Some solar farms are being built to serve other states. While some may object to this, panelist Fortunat Mueller noted that “We don’t grow potatoes in Aroostook County so we can eat them all.” Commerce involves producing commodities for sale, locally and elsewhere.

What are the impacts of solar farms on land use and the environment?

  • The location of solar farms is generally dictated by where: (1) distribution lines have capacity to accept more power; (2) land is available; and (3) there are no sensitive areas/habitat present.
    • Panelist Brooke Barnes estimates that 1 in 10 parcels evaluated are found to be suitable for solar.
  • Solar panels do change the ecology of the site – different critters will occupy areas in and around the panels. Depending on the land cover prior to the solar development, the solar farm may increase habitat diversity in the area (meadow and scrub/shrub instead of uniform forest, which is common in Maine) and create a more complex ecology.
  • Change in land use – from open land, hayfield or forest. (Decommissioning bonds provide for removal of the panels at the end of the lease, if it isn’t renewed.)
  • Land consumption. For context, buildout of solar to achieve MWW’s goal of 7,500 MW would occupy 20,000 to 22,000 acres or 0.1% of Maine’s land.
    • Fun fact: Golf courses in U.S. occupy land that could generate 370 GW of solar.
  • Solar panels do not leach toxic substances into the land. Typical solar panels are inert, made of steel, aluminum, glass, and silicon. (Thin film panels are an exception – they contain cadmium but it is encapsulated.)
  • Solar treads fairly lightly on the land. There is a slight effect on how rainwater moves across solar farms, but rainwater percolates into the ground as before.
  • Decommissioning bonds provide for removal of the panels at the end of the lease if the lease isn’t renewed. Racks are pulled out of the ground. Because of the value of the raw materials in the panels and racks, expect a robust recycling effort. Not much of a market in U.S. yet because of the small number of 30-year-old panels, but it will come.
  • Grazing is being used on a limited basis in Maine to control vegetation on solar farms, but DEP has concerns about animal waste runoff from grazed areas. The primary alternative to grazing is mowing.
  • The impact of manufacturing of solar panels is equivalent to most other manufactured products, including energy consumption. It takes 1-3 years for solar panels to replace the energy used in their manufacture.

Can we steer solar farms away from natural areas and direct them to parking lots, rooftops, landfills, and already developed areas?

  • Parking lots and rooftops are around 25% more costly to develop, because:
    • Small-scale (5 MW solar farm needs about 20 acres)
    • Structures have to be stronger and taller (people and cars underneath), so more engineering, more steel.
    • Maine could, like Massachusetts, choose to incentivize solar on parking lots.
  • Landfills are costly to develop as solar farms because you can’t penetrate the ground, and they don’t provide the acreage Maine needs to reach MWW goals.
  • We can’t reach Maine’s climate goals for solar without large-scale installations.
  • They should be kept away from special/sensitive places, but we should be careful not to make it impossible to site them anywhere.
  • Solar is being built next to existing power lines in places (e.g. Farmington, Unity). Solar farms can’t be built within transmission corridors due to need for access and requirement that CMP not be a party to energy production.
  • Solar along highways?
    • In Augusta, there are some solar farms along interchanges. More may be coming.

What are the benefits of solar development?

  • Renewable energy that can be located almost anywhere (depending on size, site sensitivity, and proximity to grid)
  • It can be built relatively quickly compared to other forms of energy
  • Helps Maine reach its climate goals
  • Land can easily return to prior use at end of lease
  • Farmers and forestland owners receive steady annual income from lease payments associated with leased land.

Are there resources to help consumers navigate the many different options to participate in community solar?

  • Two primary models of community solar
    • Ownership-based – You own a portion of the solar farm and have to contribute to the upfront capital cost. The energy you receive is proportional to your ownership stake.
    • Subscription-based – requires no upfront money, you get a portion of the generation which is discounted 10-15% from what you would pay the utility otherwise. Most community solar uses this model.
    • Maine’s Public Advocate’s offers a consumer guide to community solar.
  • ReVision Energy has a webinar on Community Solar that explains the two models on its website