Generac Grid Services Blog

I was recently invited to meet with a class of students studying energy and the future, and as a part of the session, I was asked to prepare a challenge for the students to work through. The result was interesting and showed a glimpse of what may lie ahead. It will certainly be a challenge that will require innovation, new concepts and a lot of hard work.

I showed a small area, powered by an electric utility (20% of total energy), natural gas (25% of local energy) and petroleum products (45% of total energy). The electric utility had capability to increase its energy delivered by about 25% in the next decade, and the students were asked to show how to minimize the emissions in that timeframe. They were free to add solar thermal or solar PV capacity to the system.

Climate action is on most people’s minds these days, and many view it as an industrial problem that governments can force industry to solve. But given that the International Energy Agency has identified the SUV as the second largest cause of the global rise in carbon dioxide emissions over the past decade, it’s clear that climate change is not just an industry problem. In fact, it’s been stated that if SUV drivers were a nation, they would rank seventh in the world for carbon emissions.

Climate change is everyone’s problem, and careful thought and planning are needed to reduce fossil fuel emissions with minimal impact on our quality of life and cost of living.

Everything you always wanted to know about power systems but were too afraid to ask

Part 1 of Malcolm Metcalfe's Power System Primer

There are two distinctly different methods used to balance supply and demand. These are:

1. Balancing supply/demand in an isolated system (one that is not interconnected with the larger grid. Examples are local systems to power a remote location).
2. Balancing supply/demand in an interconnected system, where a utility is a part of a major interconnection of many utilities.

The US Energy Information Administration (EIA) suggests that the multi-year historical average for transmission and distribution losses in the US power grid are approximately 5% annually (average of annual losses in 2014 through 2018).

More recent data for 2018 suggests that the loss has increased to 6.6%, which, by any account,is significant. Put in perspective, the actual loss in 2018 amounted to 275 TWh. The average retail price of electricity in 2018 was $105.30/MWh, meaning that this loss was valued at $29 billion. The increase in loss from about 5% to more than 6.6% has resulted in increased costs of loss by almost $7 billion.

What is causing the increased loss, and what, if anything, can be done to manage it?

From mainstream media to social media, the world is abuzz with the topic of climate change.  A simple Google search on the phrase today yielded 1,100,000,00 results, and typing “gret” into Google is all it takes to bring up 107 million stories about Greta Thunberg.  This 16-year-old Swedish environmental activist whose lone mission to protest climate change outside the Swedish Parliament has ignited a flame within millions of young people from more than 100 countries who have joined her with demands for climate action and a cry to “listen to the scientists.”

Even those associated with the oil industry are taking up the charge. For example, the former CEO of BP, Lord John Browne, is speaking globally about the need to clean up the atmosphere and reduce reliance on fossil fuels. His new book “Make, Think, Imagine” considers whether our demand for energy has driven the Earth’s climate to the edge of catastrophe and suggests that the same spark that triggers innovation can be used to counter its negative consequences and that it is time to “listen to the engineers.”

I recently reviewed an EPRI document that discussed storage, and by far the largest size storage systems were pumped storage plants.  I wondered why they did not include hydro (non-pumped) storage, as this form of storage is far larger than any other form of storage that is available on the grid now.

Parts of North America, but sadly not all of it, are blessed with mountainous territory that has many rivers and streams that run downhill, and many of these have been harnessed for electricity production. While not specifically intended as storage plants when built, the value of their storage may well turn out to be larger than the value of the electricity that they may produce.

Consider a hydro dam that is 35 M in height with a reservoir that is 10 km². Discharging the top 1 M of water through a generating station (90% efficient) would release almost 840 MWh of stored energy. This is a small hydro plant, with a small reservoir behind it, yet the storage is almost 840 MWh/M of depth that is drawn from the forebay.  That is in addition to the electrical energy generated for use.

So how does a utility that has no pumps manage to store and return energy?  The process is both simple and efficient.   

There is no doubt that we are facing real problems with climate, fossil fuels and carbon emissions, but as we look to solve these problems, I think that we need to look carefully at the underlying facts, rather than focusing (as some do) on the short-term elimination of fossil fuel.

1. The biggest sources of emissions in the US are the generation of electricity from coal and transportation-related emissions (60% of which is for personal transportation). These two sources are responsible for more than 2/3 of total emissions.  Canada is only slightly better, in that its electric system generates almost 60% of total energy with hydro, and nuclear is a large contributor to clean electricity as well.  Canada’s petroleum industry ranks second, behind transportation.
2. Electricity provides less than 20% of total energy, and the remainder is almost all fossil fuel. The average person gets fuel in three forms: electricity, natural gas and transportation fuel (gasoline or diesel fuel).  Any major reduction in the direct delivery of fossil fuel will be expected to be replaced with electricity, and that may be a big challenge, given the fact that the electric grid at present delivers only about 20% of the total energy.
3. Many people seem to think that if they can convert their current electricity use to solar energy, the problem will be solved. They tend to forget, however, about heating and transportation fuel. In most cases, the fossil fuel energy is far larger than the electrical energy delivered.
4. I keep hearing that the problem is someone else’s fault – blame India, China, the oil industry or the government. We all need to look in the mirror – and recognize who the big users are.  The fact is that North Americans are among the largest users of energy per capita in the world.  As “Pogo” would have said, “We have seen the enemy, and it is us!”

There are two areas to look at: the supply of energy and the use of energy.

For more than 100 years utilities have supplied electrical power to customers and have done so with good reliability. The principle is simple. Loads may do as they wish. They may be random or intermittent and generally are not individually monitored by the utility.  Generation, on the other hand, MUST be both dispatchable and monitorable, and electric system operators must be able to manage the real and reactive power from a generator.

Historically, utilities have become very adept at managing generation capacity to maintain a continuous balance between supply and demand. But today, the world is faced with a need to reduce or even eliminate carbon emissions, which complicates the supply-demand balance. Most electricity in the US, for example, is generated by burning fossil fuel. This needs to change, along with change to the electricity supply system and the direct customer use of fossil fuel.  We are looking to remove the steady performers, and to replace them with supplies that are intermittent and perhaps random, all the time maintaining a balance between supply and demand.

The California Duck Curve reveals a potential costly issue for utilities and their customers. The annual peak load appears to be continuing to grow -- because it occurs after dark when there is no solar power being generated -- yet energy sales may be declining with the growth of distributed solar generation during the day. This results in the need to continue to expand the grid, but without the sales revenue to support the added capital expense, presenting a Catch-22 that utilities are struggling to overcome.

For more than 100 years utilities have supplied electrical power to their customers and have achieved this with good reliability. The principle is simple. Loads may do as they wish, but generation — the supply — MUST be both dispatchable and monitorable. An operator must be able to start or stop a generator or to change capacity at the touch of a button to maintain a continuous balance between supply and demand.  On the other hand, the loads that use the electric power can be intermittent, unmonitored and subject to starting and stopping at what the system operator would see as near random times. 

Suddenly, the world is faced with a need to reduce or even eliminate emissions.