The Challenges of Renewable Energy

A couple of article in the Chesapeake Bay Newsfeed today that highlight the promises and pitfalls of renewable energy. First, Pennsylvania is planning for storage of electrical energy from non-reliable renewable sources: Storage Capacity, Recommends Solar-Plus-Storage For A Cleaner, More Resilient Electric Grid

“Pennsylvania’s climate continues to get warmer, and we’ve already started seeing the impacts, with increasing swings in temperature and extreme weather,” said DEP Secretary Patrick McDonnell. “Solar-plus-storage can help in two ways: It can help slow down climate change by incorporating more clean renewable energy into Pennsylvanians’ daily electricity use, and it can also make the grid more reliable during extreme weather events, better protecting Pennsylvanians’ health and safety as well as critical facilities.”

The electric grid uses energy instantly as it’s generated, with little capacity to store. At times of high demand, such as late afternoon, peaker power plants are often used to provide extra electricity. These plants often have very high carbon emissions rates, and many are located in or near Environmental Justice areas.

The DEP Energy Programs Office commissioned Pennsylvania Energy Storage Assessment: Status, Barriers, and Opportunities from Strategen Consulting to determine the best path forward to increasing energy storage statewide.

There are currently about 1.5 gigawatts (GW) of energy storage capacity in the state. This represents 22 operational or announced energy storage projects, including traditional pumped hydro storage facilities (1.07 GW), lithium-ion batteries (18 megawatts; MW), lead carbon batteries (12.5 MW), ice and chilled water thermal storage (6 MW), and other technologies providing smaller amounts.

You can see pumped hydro storage is far and away the majority of their current energy storage capacity. For those unfamiliar, to store energy using pumped hydro, temporarily excess electricity is used to pump water to a reservoir at a higher level, to extract the energy, the water is run downhill through a set of turbines, with friction, and the second law of thermodynamics each taking their share of the energy. As you might imagine, such operations are large, and require geography that enables two large reservoirs at different elevations fairly close by.

The report recommends pairing grid-scale solar arrays with battery storage to help reduce carbon emissions and increase grid resilience. One way to catalyze this would be to set a state energy storage capacity target, as seven other states have done.

For example, to get 10 percent of electricity from solar energy, the DEP Pennsylvania’s Solar Future plan recommends increasing in-state solar energy from about 700 MW today to 11 GW by 2030. If 25 percent of this solar target were paired with a target of 1.5 GW of battery storage, Pennsylvania energy customers could save $273 million annually in wholesale energy costs and avoided public health and environmental impacts from a reduction of 2.5 million metric tons of carbon emissions a year.

At this point, batteries aren't very good option, because they are expensive in the amount required, and require substantial inputs of rare, and environmentally unfriendly to mine metal.

The other article is for nearby St. Mary's County Report: St. Mary’s County Can Meet Renewable Solar Energy Goals with Smart Siting & Wise Land Use

Today, at a meeting of the St. Mary’s County Solar Task Force, Chesapeake Conservancy’s Conservation Innovation Center (CIC) presented a new report: Optimal Solar Siting for St. Mary’s County, Maryland. Using geospatial analysis, the report identifies optimal solar sites and answers the key question: Are enough optimal sites available to meet St. Mary’s County’s renewable energy goals for solar energy while avoiding impacts to agriculture and the environment?

The analysis results showed St. Mary’s County offers significant optimal opportunities for solar placement in the existing built environment that would minimally impact the natural landscape or prime agricultural land; including on rooftops of commercial and residential buildings, above parking lots as solar canopies, on capped landfills, around the Marlay-Taylor Wastewater Reclamation Facility and on county-owned properties. Other additional preferred solar opportunities were also identified.

Maryland is one of 30 states in the United States with a Renewable Portfolio Standard (RPS), a mandate to increase electricity production from renewable energy sources. Maryland’s mandate requires 50% of electricity sold by utilities to come from renewable sources, with 14.5% from solar. While the Southern Maryland Electric Cooperative (SMECO) that serves St. Mary’s County is excluded from the 14.5% carve-out and is instead required to reach a solar carve-out of 2.5% of retail sales, land in St. Mary’s County could still be used for solar energy installations to meet statewide goals outside SMECO’s service area.

Solar installations range from small rooftop photovoltaic systems and medium-sized distributed generation installations that use energy locally and feed excess energy back to the grid, to large ground-mounted installations that sell energy directly to utilities. The Governor’s Task Force on Renewable Energy & Siting estimates that the land needed to meet the state’s RPS goal will require between 7,750 and 33,000 acres of land across the state. The task force report determined that may impact between 0.4 and 1.7% of available farmland, and between 0.7 and 2.9% of available prime farmland, in Maryland, and wrote, “While small in aggregate, the encroachment of utility solar on prime agricultural and farmland remains a serious concern to rural communities, policymakers and stakeholders.”

Just for reference, 33,000 acres is equal to 55 square miles. That's a lot of land to take out of agricultural production, or the just cover up with masses of solar cells (which, much like the rechargeable batteries called for in Pennsylvania, are relatively expensive, have a fairly short life span, and are made from exotic, toxic and expensive materials, mostly in China. 

Making nuclear power look better and better.