Corporations crunch a lot of numbers on a lot of things but businesses, just like consumers, don't have a very good grasp on energy spending.

Software start-up ENXSuite today is releasing an updated version of its energy management software, one of many companies trying to bring stricter accounting to costs related to natural resources, including water, waste, and greenhouse gas emissions.

ENXSuite, which has some 24 announced customers, competes with start-ups Hara Software, which launched last year, and C3, a still stealthy company with Tom Siebel and Condoleezza Rice on its board. Companies in more specialized areas, such as building management or demand response, are trying to bring better control over natural resources.

ENXSuite's software is designed for understanding energy consumption and managing efficiency or sustainability projects.

The activity reflects how spending on energy is typically not well-understood or actively managed by big organizations, said Beatriz Infante, the CEO of ENXSuite, a former Oracle executive who joined the company in June.

"We've been managing energy at the facility level. But at the corporate level, there hasn't been a system of record of how you're spending and how you're managing electricity or the gas bill," she said. "An important component is being the system of record."

The company's software enables businesspeople, either financial executives or sustainability officers, to track usage of electricity, gas, water, waste, or greenhouse gases. Once that data is collected, people can create models to make decisions on energy efficiency initiatives.

For example, a company could compare the payback period of investing in data center virtualization versus an efficient lighting program. Then, companies or municipalities can monitor the progress of these projects and even tie the results to employees' compensation, Infante said.

Version 6 of the application can now automatically get energy usage data from utilities. ENXSuite partnered with data providers which get data on electricity and gas usage, which is fed into the ENXSuite application, Infante said.

"At large enterprises, a big integration challenge is how you get the data. Think back to before sales force automation, when everybody used spreadsheets," she said.

Large enterprise software companies are already moving into the energy and sustainability management business. SAP bought a software start-up that tracked energy and carbon emissions last year, which is now part of its sustainability dashboard product.

ENXSuite was originally named Carbonetworks and focused on managing corporate carbon reduction programs. Infante said that the company is now focused on energy and other natural resources because they are direct costs.

Even though an economy-wide cap on carbon emissions won't be put in place in the near future, companies do need to deal with EPA regulations and the rising cost of energy, she said.