The New York State Electric Grid--Part 1
April 15, 2019, by Laura Burkhardt
New York environmentalists are working very hard these days to achieve the 45% reduction below 2010 emission levels that the 2018 IPCC Global Warming Special Report from the UN tells us is essential in limiting rising temperatures to less than 1.5° C. One of the main findings in this report is that we are currently on track for 3°C rising. Limiting the rise to 1.5°C by 2030 will require “rapid, far-reaching and unprecedented changes in all aspects of society” and will still result in climatic difficulties, but will have markedly better results for the planet.
One focus in this effort is on the electric grid. An important component of Gov. Cuomo’s Green New Deal that was announced in January 2019 was an increase of New York's successful Clean Energy Standard mandate from 50 percent to 70 percent renewable electricity by 2030. To see how this goal can be achieved, it is necessary to first understand how the grid works – how electricity travels from a fuel source such as fracked gas, sunlight, wind, or hydropower to our homes and businesses. When we hear about this mandate, we tend to think immediately of building more solar and wind farms and shutting down existing fossil fuel plants, but when we understand how the grid works we will see that there are a number of other strategies that are available to achieve this goal.
Physical Components of the Grid
The physical components of an electric grid and their corresponding functions fall into three main categories: Generation, Transmission, and Distribution.
Generation. In a generation facility, electricity is generated from a variety of sources: fossil fuels (gas, oil, coal), nuclear reactions, and renewable sources (solar, wind, hydropower). This electricity then goes to transmission substations. These electricity producers can be for-profit power plants (e.g., CPV, Cricket Valley, Danskammer), local solar farms (e.g., Wawayanda), etc.
Transmission. At transmission substations high voltage transformers step up the voltage in order to send the electricity on high-voltage lines, such as those that hang between tall metal towers. This electricity travels over long distances to local area substations; higher voltage is more efficient and less expensive for this long-distance transmission. Historically alternating current (AC) was used for such transmission but the advent of high-power electronics made the use of direct current (DC) possible. High voltage DC has a smaller transmission loss than high voltage AC and is mostly used where AC can’t be used (for example, longer lines under water) or where lots of power must be transported over very long distances.
At local area substations transformers then step down the voltage so it can be distributed using alternating current (AC) by local utilities to neighborhoods.
Distribution. In this step, distribution lines owned by local utilities carry electricity to consumers. Transformers on street poles step down the voltage further before it enters buildings; lower voltage electricity is safer for use in homes and businesses. Local utilities may purchase the electricity through a wholesale market organized by a regional transmission reliability organization (in our case, the New York Independent System Operator, NYISO) or directly from independent power producers or from other utilities.
See the September issue of Terra Firma for Part 2 of this continuing series on the grid in New York state.
Sources
[1] 2018 Intergovernmental Panel on Climate Change Global Warming Special Report
[2] https://www.eia.gov/energyexplained/index.php?page=electricity_delivery
[3] https://www.quora.com/Why-is-high-voltage-AC-used-in-power-transmission-lines-instead-of-DC-and-or-higher-current
[5] https://www.nyiso.com/what-we-do
[7] https://www.ferc.gov/market-oversight/mkt-electric/new-york/2007/04-2007-elec-ny-archive.pdf
[8] https://www.ferc.gov/market-oversight/mkt-electric/new-york/2007/04-2007-elec-ny-archive.pdf