Archive for June, 2012

Low Power Hour!

Yesterday, Hollins hosted its first-ever “low power hour.”  We recently enrolled in a “demand response” program, which requires that we reduce our electric consumption by a predetermined amount on grid emergency days.  To ensure that we can actually make good on our commitment, the grid operator will often hold a “test event” requiring us to curtail usage for an hour.  Thus, “low power hour” was born.

While we won’t have the final results of the test for a few weeks, the preliminary data suggest that we did pretty well.  Take a look at the graph below too see results:

It was an interesting experience, and I learned a lot in the process.  I was particularly surprised by its success given that this was was organized  only 48 hours in advance.  No long PR push, no boots on the ground or students knocking on doors.  We put up a few notices on our internal site and sent out a few email blasts.

The other part of the success was not just that people were compliant, but that the changes stuck much longer than expected.  Our test event was only an hour long, from 12 to 1.  You can see from the graph (which ends at 1:45) that we were still lower than the previous day afterwards. This continued for the most part until 5 PM.

I’m heartened by the results of this event.  One of my primary goals as an energy manager is to encourage conservation behaviors, which requires changing habits and attitudes. When I came into the office this morning, I noticed a few offices with their lights off, which is great to see.    We’ve been heading in the right direction for quite some time, but this event highlighted some of the positive changes we’re starting to see around campus.


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What does a hot day mean for the grid?

As you may have noticed it’s now officially summer and the weather is warming up.  What you may not know is how much weather impacts energy consumption, especially during the summer.  As the temperature rises, electric grids experience more load and will eventually reach their capacity.  That’s one of the reasons we have regional transmission organizations, or RTOs.  Here in Virginia, we’re part of the largest RTO in the US called PJM.  The RTO oversees the generation and transmission of electricity in its particular region to ensure reliability. They also oversee the wholesale electricity market.

An important thing to remember is that production of electricity is not a flat price for generators.  Even though our bills in Virginia have just one rate per kWh, the utility’s cost varies depending on what time of day and the amount of demand.  Just like in Econ 101, price and demand tend to change together.  For example, here is today’s load curve for PJM:

Time of day is on x-axis and demand is the y-axis.  As the day goes on, the demand for electricity increases.  As demand increases, the utility’s cost to produce power also tends to increase.  Compare that to yesterday’s locational marginal prices (real-time prices at different parts of the grid):

Each one of those lines represents a different zone in, and they have different price points and curves.  They tend to be pretty close together, but some locations are higher or lower than others depending on demand, fuel source, and generator capacity.  It’s much more complex than the simple x per kWh rate that you see at the end of the month, but some parts of the country are moving to a dynamic pricing model with variable rates during the day.

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The continued decline of coal

Electricity generated from coal is at a 40-year low.  Low natural gas prices, a warm winter, and tightening regulations have resulted in many utilities switching from coal to gas.  This graph says it all:

You can see the seasonal variations in generation and as you get to this winter, coal begins to fall off (as natural gas gradually increases).  Even Appalachian Power, our coal-based local utility is jumping on the gas bandwagon: “Natural gas is the bridge fuel to America’s energy future and is likely to be the only source of new fossil-based generation.”

There is still considerable uncertainty regarding what will displace natural gas when supplies diminish and/or prices rise.  Until then, though, it looks like natural gas will be supplying an ever-increasing share of our electricity.

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The importance of real-time feedback

One of the biggest challenges in promoting energy conservation is that the people generally don’t know how much energy they use in a given day.  The only real data we tend to get are at the end of the month, when our electric or gas bill arrives.  This is compounded by the fact that energy is more or less invisible these days.  A century ago, most people were more engaged with their energy sources, like chopping wood for their home furnace, and this activity helped make the cognitive link between activities (turning up the temperature in the house a few degrees) and the amount of energy required (an additional cord of wood).  Today, we turn up the thermostat or flip on a light without any direct link to the fuel it requires to complete that action.

I came across a great analogy recently, where the author compared this experience of only receiving a bill at the end of the month to grocery shopping, except that you’d be shopping in “a store without prices on individual items, where [you are] presented only one total bill at the cash register.  In such a store, the shopper would have to estimate item price by weight or packaging, by experimenting with different purchasing patterns, or by using consumer bulletins based on average purchases.”

I can’t imagine how difficult that would be, but luckily we don’t (usually) have grocery stores like that.  Unfortunately, most of our energy systems still operate on this communication model.  We receive only a single bill after we’ve consumed that month’s energy, giving us only one good opportunity to alter our behavior in response to the bill.  Usually this motivation wears off in a few days, unless the bill was substantially higher than previous ones.  To reinforce conservation behaviors, occupants need feedback.

That’s why real-time energy dashboards, where the building occupant gets a constant readout of how much energy they’re consuming (in a graphically pleasing format), have proven to be very effective.  For a long time, the popular belief was that people just didn’t care and that’s why they were disengaged.  But what we’re seeing these days with advancements in technology is the power of feedback loops.   Think of the unmanned speed limit reminders that tell you (and everyone on the road) how fast you’re going compared to what the legal limit is.  There aren’t any consequences to speeding at that moment, but these unmanned speed traps are tremendously effective because they include a prompt (a flashing 85 MPH) that is easily understood by a speeding car, which results in a change in behavior (slowing down until the sign stops flashing).

Research has shown similar levels of success for real-time energy dashboards.  It turns out that, oftentimes, we’re not lazy or negligent but rather we’re in need of the right kind of information.  People cut back consumption 10-15% when they have access to that information.  Real-time feedback is just one tool we can use to engage occupants, and my job is to find the best blend of information, incentives, and outreach that gets us the lower energy consumption numbers we’re after.

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Fun with graphs

As part of a renewable project that I’m working on, I was asked to provide the lowest peak usage for our campus during a given year.  It’s usually relatively easy to find our highest peak usage because it shows up on our bill every month, but to find the lowest peak I had to get 12 months of data from our utility and sort through it (and by “it,” I mean 19,685 data points).  The result is the chart below, which I’ve affectionately named the kW drip chart.  Instead of seeing the normal demand curve and looking for the highest point, you’re seeing the inverse.  Looking at the chart below (from E&H), you can see that our lowest campus peak (during 9am-3pm daily) was on Christmas Eve (followed closely by Thanksgiving and spring break).

So, what does this say about our consumption patterns?  Well, we know that our highest peak during the summer (air conditioning uses a lot of energy), so that explains part of the graph.  But if you look at early May (on the far right of the chart) you’ll see a pretty big dip, even though it’s during cooling season.  What happened then? Well, we had a lull between the end of the semester and the beginning of summer programming.

What this chart reinforces is the fact that our electricity consumption is primarily driven by people.  That may seem fairly obvious, but often many people feel that their individual behaviors don’t have an impact on what we consume as a campus. In a way, they’re partially right, because individual actions don’t have a measurable impact on our total consumption.  But we see below that when the majority of campus does something in unison, it has a huge impact.  This could be as small as turning up the temperature in your office 2 degrees in the summer, or switching to task lighting instead of overhead lighting.  So don’t despair that your good conservation behaviors aren’t helping, because this chart shows that good things can happen when we all band together.

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Solar power is older than you think

Check out this link to see an interesting timeline of the history of solar cells.  We often think of them as a symbol of cutting edge technology (which many are), but the concept of solar power has been around for many decades. The first solar cell was created in 1883, and panels have been used on spacecraft since the early 1950s.

Both Hollins and E&H are considering the use of large-scale solar power on our campuses, but the current regulatory structure in Virginia makes it difficult to accomplish at a reasonable price.  That being said, higher education institutions have been leaders in solar power, and we hope to become a part of that leadership in the future.

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