Control and Reduction of Peak Power Loads

Peak power loads are high points, sometimes spikes in demand for power. Peak loads are a problem for utilities and their customers alike. For utilities, peak loads must be balanced with supply to avoid power shortages. When the utilities can’t respond quickly enough with their own power, they need to source power on the open market, where price spikes of 1000% or more are possible. Utilities will often attempt to reduce the occurrence of demand spikes by charging power users higher rates for peak power. It’s then incumbent on the customer to reduce or eliminate spikes in power consumption to avoid those charges.

Peak Power Background

In buildings, peaks in power usage are often, but not always associated with a high demand for cooling on summer afternoons. Aggregations of power users all using their air conditioning at the same time result in demand peaks. It shouldn’t be surprising that these aggregations of power consumption are hardest to control because they are all independent of each other and are all responding to the weather, which is out of their control. On the other hand, larger consumers of power may be better able to reduce their peak power consumption by taking steps to reduce power purchases during these peak times. This is possible either by anticipating power peaks and taking proactive steps to reduce demand from the utility during those times, or by supplementing with other power sources.

Utility Rate Structures for Power

Energy Rate

Utilities charge for the power they produce by charging for delivered energy. Energy in the form of electricity is sold in units of kilowatt hours (kWh). Along with a charge for distribution, the energy charge covers most of the costs incurred by the utility for the power it produces and delivers. What these charges do not cover are the added fixed and variable costs associated with peak power production and delivery.

“Demand Rate” for Peak Power Consumption

Where the utility has reliable base load but is challenged in meeting peak loads, they may institute a demand rate billing structure. The demand rate structure imposes a higher charge for power consumption at peak times. The demand rate structure is common in industrial and large commercial application, and has been seen in some residential applications as well.

Responding to Demand Rates

As utilities impose demand rates as a response to their challenges is meeting peaks in demand, a logical response by the customer is to lower demand at those times. If a utility charges different rates depending on time of day, the natural response is to buy energy at the less expensive time of day, and use it when rates are higher. An example of this is when a power buyer makes ice at lower rates, and then melts the ice for cooling purposes during peak rate hours. This is great for cooling, but if electrical energy is what’s needed at peak hours, then other solutions are needed.

Combined Heat & Power (CHP)

CHP is a technology that large energy users can turn to for producing their own economical baseload power, while also reducing peak levels of purchased power. As described on the CHP post, the technology can be cost-effective on its own, in economically producing heat and power, and by increasing the reliability of power. The cost savings CHP can offer by avoiding costly demand rates can also be compelling.

SCADA

Demand control for large energy users can also be accomplished with SCADA applications. From a simple metering device with peak demand warning to a full monitoring network, SCADA can be used to reduce power usage automatically or manually, as needed. This type of demand response is appropriate in situations where reducing power consumption in an ad hoc manner is realistic. Therefore, this may not be a good option for hospitals, hotels, and commercial buildings.

Throttling down, or completely shutting off power to one or several powered items is called load shedding. It makes sense to shed load from one application in order to temporarily provide load somewhere else, and when the power is constrained in some way. The constraint may be peak power pricing, or it may be a limitation in the power infrastructure. In any case, load shed is most often a temporary measure, and SCADA can be used in that way.

Conclusion

Building owners and operators have multiple avenues available for reducing energy costs through peak shaving. Having a working knowledge of these options is a step in the right direction. Contact CIMI Energy to find ways to reduce your energy costs.

Additional Resources

The Peak Load Management Alliance exists, with more detailed information about peak loads and demand response.

January 5, 2017November 5, 2018

Distributed Energy

A powerful business case can be made for harnessing distributed energy, making it a fast growing category within the energy field. The fast pace of growth results from a combination of the maturation of a variety of alternative energy technologies, and the unwinding of utility regulation. The alternative energy technologies that typically comprise distributed energy provide building owners with the ability to cut energy costs, increase energy efficiency, reduce carbon emissions, increase reliability, and eliminate peak utility charges.

The Energy Market Transforms

Distributed energy equipment suppliers have invested heavily in hardware and software in order to achieve the goal of safe and dependable integration with the grid. Having achieved this goal, the available options for building owners to utilize alternative energy have broadened out.

A “mature” distributed energy sector means that all aspects of a distributed energy network operate safely, predictably, reliably, and cost effectively. Tying in new energy sources becomes a straightforward matter, and doing so does not adversely affect production and distribution from other parts of the grid. A mature sector also means that the power produced meets acceptable standards.

As noted above, deregulation of energy markets has been a driver of growth in distributed energy as well. With the elimination of utility monopolies, competition from new sources of power give organizations a choice in where they get their power. Among the available choices for building owners is to produce their own power, in whole or in part. In such cases, consumers become producers as well, leading to the label “prosumer”*.

With distributed energy, power sources can be placed on-site (such as on-site CHP), or off-site, such as from renewable energy sources like solar, wind, and biomass (usually as CHP). The power sources need not be local, as innovative energy contracts allow buyers to purchase the output from remote energy sources.

The Impetus for Distributed Energy

For building owners, making an investment in distributed energy must of course make sense from a timing perspective, as something that’s working is not ordinarily high on the priority list for change. The initial impetus that shifts an organization’s “energy inertia” can come from failing energy assets (such as a heating or cooling system that breaks down), or simply an energy audit that reveals costs above achievable benchmarks.

In most cases, there are several benefits that can be identified in advance. Opportunities in cost savings, as well as in enhanced efficiency and increased security and reliability are usually all present when the decision is made.

Benefits of Distributed Energy

Cost Savings

The most salient reason organizations give for choosing a distributed energy solution is to save money. The IRR (internal rate of return) for investing in distributed energy must be greater than the anticipated return offered by alternatives, including not doing anything (i.e. maintaining status quo) if that is a possibility.

With the fast pace of advancements in energy systems in recent decades, there are often good cost savings available just from reduced maintenance and repairs. By incorporating the right solutions at the outset, an on-site CHP project such as producing electricity while making process heat, space heat or hot water can bring predictable cost savings to the user.

Efficiency

Decentralization can also lead to higher efficiency where energy assets allow more energy to be captured from the fuel. A great example of this is when an organization produces it own power, and at the same time captures the “waste” heat for some internal process. Combined Heat and Power (CHP) is inherently more efficient than a case where standard power generators are used.

Higher system efficiency is to be had where companies with large electricity demand such as server farms (e.g. IT Services, ISPs, Amazon, Google, and other cloud services) are locating in out-of-the-way places that are newly served by the expansion of distributed energy. Server farms create a lot of heat, so their locations are often being located where electricity is cheap, and either where the climate is cool (making cooling the equipment much more efficient), or where the waste heat from the server farm can be used for some other purpose.

Security and Reliability

The electric grid is old and suffering from technological senescence. It is vulnerable to damaging natural and man-made events. Flooding events that cause power outages are more threatening than they used to be, particularly alongside rivers and sea coasts where much of the traditional power producing infrastructure is located. Wind storms, ice storms, fires, and human threats are thankfully uncommon, but real enough to be taken seriously.

Businesses rely on power. Distributed energy makes the power supply more reliable for those businesses with the foresight to take advantage.

Reduced Carbon Emissions

Alternative energy sources reduce carbon emissions. This result is caused either through the higher utilization of the energy content of fuel (i.e. efficiency), displacing a high-carbon fuel with a lower carbon fuel, or through the utilization of some form of renewable energy, such as wind or solar.

Hedging Against a Possible Carbon Tax

The idea of imposing a carbon tax is routinely discussed in Washington these days. Supporters include market-oriented conservatives, and progressives concerned about climate change. If a carbon tax were to be passed into law, it will be advantageous for organizations to be positioned with low-carbon utilizing assets in place.

For energy investments in durable goods expected to last 5 years or more, the possibility of a carbon tax is definitely something to weigh.

Eliminating Peak Power Charges

By providing an alternative source of energy to traditional utility-provided grid energy, additional cost savings can be secured by avoiding peak energy charges. More on this topic will be available in a separate blog post on this topic.

How to Proceed with Distributed Energy

What is required to reach cost savings, efficiency, and reliability goals with distributed energy is good planning, modelling, and execution. These are essential to achieve long-term success. Working with a team that has experience with all these working parts, and which is willing to learn about your businesses’ energy needs is probably the best way to achieve success.

CIMI Energy will serve as a conducer*, working with you and your internal team to ensure a successful result.

*An equivalent producer/consumer word blend to “prosumer” is “conducer”. But what I thought might have a lower chance of getting baked into the language, “conducer” is, as it turns out, an actual word in the dictionary. It means “a person or thing contributing to a specific result” 🙂